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Discussion Starter #1 (Edited)
I thought I'd start this thread for FAQs about the MegaSquirt PNP, and specifically the MSPNP versions out there for the Probe and MX6. If you've got other questions, let me know - if it's likely a lot of owners will be asking it on this forum, I'll add them to this top post.

So, just what is the MSPNP?

The MSPNP is a plug and play, standalone engine management system that lets you control your fuel and ignition, as well as many other functions, such as boost control and cooling fans.

What Probe and MX6 does the MSPNP fit?

Currently, the MSPNP is available for 1993-1995 Probe and MX6 models running either the KLDE or KLZE V6. A version for 1990-1992 models with the F2T engine is in testing.

What about MSPNPs for cars not on the to-do list?

If we have the connector in stock and you can organize a group buy, we can put it on the list. See the MSPNP On Demand program for details. So, if you want one for your '88-'89 F2T or the FS motor, it could happen if we have enough people on board.

Does the MSPNP allow tuning in real time?

Yes! You have complete control over your fuel and spark tables, and changes to those take effect immediately. You can tune it while it's on a dyno or while the car is running around a track - although if you're tuning it at Road Atlanta, we recommend wrapping up your tune changes by the end of the back straight, as tuning while going through that chicane before the Suzuki Bridge and then plunging into Turn 12 like a roller coaster can be distracting.

Do people really ask about tuning from the passenger seat while running around Road Atlanta?

Sorry, that's only happened once. We'll try to stick to more common questions from now on.

Can I remove my mass air flow sensor or vane air flow meter using an MSPNP?

Yes. The MSPNP has a built in MAP sensor, letting you run speed density. This means it has no need of a mass air flow sensor, and you can replace yours with a length of straight pipe if you're so inclined. We've often seen a measureable horsepower gain from this on a dyno, particularly if you have a vane style air flow meter like most Probe and MX6 models used.

You said the MSPNP runs speed density. Does it support other load modes?

Yes. It is possible to set it to use a mass air flow meter, although you will need to generate a calibration curve for your MAF - there's an internal switch that swaps the MAP sensor input for the factory load sensor. It also allows alpha-N operation (using a throttle position sensor for fueling) or even blends of alpha-N and speed density. The software has a special ITB mode that uses the MAP sensor at low throttle / high vacuum and switches to the TPS at high throttle / low vacuum, for those using independent throttle bodies.

Do I need to make any changes to my wiring or sensors to run an MSPNP?

MSPNPs can run a car with all stock sensors and its built in MAP sensor, with one important exception. On a motor with forced induction, you'll need to add a post-intercooler IAT sensor. We recommend putting it in between the throttle body and intercooler. Putting it in the manifold is also an option but may make hot starts more difficult. The IAT sensor is sold separately for the KLDE / KLZE models; it will probably be included with the F2T MSPNP.

How much boost can I run with an MSPNP?

All of it. The MSPNP has a 4 bar MAP sensor as standard equipment, which can read up to 44 psi. In the unlikely event that is not enough, it is possible to use an external MAP sensor that reads higher. As long as your fuel system can supply enough fuel and your engine is tough enough to handle it, you can tune for it with the MSPNP.

Can I have two maps in it? Like one for power and one for fuel economy?

The MSPNP has a switch input to allow switching between two fuel and ignition tables. However, we have generally found that a good tuner can produce a table that gets both maximum power and good fuel consumption, so we don't recommend trying to create separate power and economy maps. Good uses for this feature include a pump gas and high octane race gas map, one map for wide open exhaust and a second for tracks that require a muffler, or switching to the second map when a nitrous system is active in order to pull timing and add fuel.

Is the MSPNP emissions legal?

The MSPNP is sold for competition use on race tracks, autocross, drag strips, off road courses, and things that otherwise don't get driven on public roads. Although a correctly tuned MSPNP is capable of relatively low tailpipe readings, a badly tuned one can send emissions through the roof. Consequently, installing one on a street car does not meet Federal emissions rules. If you have to return your race car to street duty, you've got to unplug the MSPNP and go back to the stock ECU to stay street legal.

If you're outside the USA, you'll have to check what your laws are over there. Other countries are sometimes more lenient.

Where are MSPNPs made?

The case and PCBs are made in the USA, and all assembly work is done in the USA as well. The connectors, transistors, and other electronic components come from all over the world, so they can be advertised as "Assembled in USA" but not "Made in USA."

Can I use an MSPNP to convert to distributorless ignition?

Yes. We've included a writeup using our QuadSpark and IGN6 coil pack in the installation instructions.

Where does the MSPNP fit in the MegaSquirt family? Is it a V3.0 or V3.57?

Neither. At its core, the MSPNP uses a MicroSquirt Module. We've added an extra circuit board of our own design to expand the MicroSquirt Module's list of features.
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